Carburetor



Patented dune lddl unite anti WELLIAM C. CARTER, (Mi FLEET, MICHIGANcnanroa Application filed April 22, 159%.. serial Ito. 350,100.,

This invention relates to carburetors of the type that are equipped witha plurality of venturis or suction amplifiers.

One object of my invention is to provide a carburetor oi the generaltype mentioned,

that is equipped with a means by which the operator in charge of theengine on which the carburetor is used, can cut on the supply oil air toall of the venturis or suction amplifiers to in zero or extremely coldweather, and cause air to be drawn directly into the fuel passageway ofthe nozzle or main fuel supplying element of the carburetor so as toproduce an aerated charge of fuel that facilitates startila ing theengine;

Another object is to provide a carburetor of the general type mentioned,i. e., a multi-venturi carburetor, in which the venturi that producesthe first stage of suction amplificaac tion has an air inlet ofsubstantially the same diameter or of greater diameter than the outletof the carburetor which communicates with the intake of the engine,thereby makin it practicable to equip the carburetor with t at leastthree venturis which are of such relative diameter and arrangement thatthe volume of air flowing through all of the venturis will be greatenough to float the fuel or insure the particles of fuel bein carried tofreely into the main passageway o the carburetor.

Other objects and desirable features of my invention will be hereinafterset forth.

Figu as of the carburetor embodying my present invention.

Figure 2 is a vertical sectional view of said carburetor; and a Figure 3is a vertical sectional view, taken to on the line 3-3*ol Figure 2..

Referring to the drawings which illustrate the preferred form of myinvention, A designates the main passagewa of the carburetor, formed bya bore in the ody B of the carat buretor, C designates a throttle valveat the upper end of sand main passageway, D designates an air chamber inthe body of the carburetor, E designates the float chamber, F designatesa float in said float chamber that f governs a valve G which controlsthe supply re 1 of the drawings is a top plan view i fication arrangedof liquid fuel to the fioatchamber and ll designates an acceleratingwell whose upper end communicates with the air chamber l). The main fuelsupplying element of the carburetor is herein illustrated as consistingof a vertically-disposed nozzle l arranged inside of the acceleratingwell and projecting upwardly from the bottom of same, said nozale beingsurrounded by a tubular'm'ember J- of less diameter than theaccelerating well which projects upwardly from the bottom of said well,The carburetor is also equipped with a means of the general typedisclosed in my pending applications for patent Serial No. 206,030,filed July 15, 1927, and Serial No. 226,684, filed llctober 17, 1927,for supplying fuel to the main passageway A above the throttle valvewhen thethrottlevalve is closed or only partly open, saidmeans beingherein illustrated as consisting of a vertically-disposed fuel tube K(see Figure 2) mounted in the body of the carburetor in such a mannerthat its lower end communicates with a fuel-duct 1 that leads to thebottom of the accelerating well and its upper end communicates with afuel duct 2 that leads to an adjustable terminal portion K for the fueltube whose discharge end can be arranged in various positions withrelation to the throttle valve by manipulating an adjusting device 3,which I will not describe in detaihas it forms no partof my presentinvention.

As previously stated, the carburetor is equipped with a plurality ofventuris or suction amplifiers arranged between the throttle valve andthe main fuel supplying element of the carburetor and consisting of aventuri L positioned in the lower end portion of the main passageway Aof the carburetor for producing the first stage of suctionamplification, a venturi M for producing the second stage of suctionamplification arranged inside of the air chamber D, with its upper enddisposed in concentric relationship with the 95 air intake end of thefirst venturi L and projecting upwardly into same, and a venturi O forproducing a third stage of suction ampliat the upper end of the tubularmember J in the accelerating well, with 100 its u er end projectinupwardly into the air iiil zike end of the sec nd venturi M. Due to thefact that the air intake ends of the first and second venturis arearranged inside of the air chamber D, air can pass from said chamber andflow upwardly through the annular space between the lower end of theventuri L and the upper end of the venturi M and also upwardly throughthe annular space between the lower end of the venturi M and the upperend of the third venturi O. The third venturi 0 receives its supply ofair from the accelerating well H through verti cally-disposed air slots4 in the tubular member J in the well, whose upper ends terminate abovethe normal level of the fuel in the float chamber, represented by thebrokendines m in Figures 2 and 3, the upper end of thenccelerating wellbeing in direct communication with the air chamber D, so that air canpass from said chamber and flow downward- 1 into the acceleratingwellfthence inwardly through the slots 4:, and thence upwardly throughthe annular space between the upper end of the nozzle I and the thirdventuri O.

In a carburetor of the multi-venturi type it is essential that theannular passageways of all of the venturis be of great enoughcrosssectional area to permit a sufficiently large volume of air to flowthrough said passageways to float the particles of fuel and carry is inuse to insure the fuel being carried upwardly into the main passagewayof the carburetor. One convenient way of accomplishing this highlydesirable result is to provide the first venturi L with an enlargedportion having an air passageway whose side wall tapers or diverges fromthe air inlet at the lower end of the venturi whose diameter is suchthat the greatest diameter of the air passageway in the venturi L isequal to or in excess of the diameter of the main passageway' A of thecarburetor. Preferably, the venturi L is provided intermediate its endswith a throat or contracted portion that is arranged above the point of.greatest diameter of the air passageway in the venturi L. As shown inFigures 2 and 3, the enlarged portion of the venturi L that contains theair passageway of gradually increasing diameter, is mounted in a counterbore at the lower end of the main passageway A. of the carburetor. Fromthe foregoing it will be seen that notwithstanding the fact that thefirst venturi L is positioned in the main pass innate? sageway A of thecarburetor, the intake portion of said venturi hasa diameter equal to orin excess of the diameter of the main passageway A, thereby permittingthe second and third venturis M and 0 to be made of greater diameterthan would be possible if the first venturi L were constructed in theform of a tubular member of the same external diameter throughout itslength, positioned in a bore of uniform diameter in the body of thecarburetor, as has heretofore erably,.the first venturi L is mounted insuch a manner that in moderate weather the operator can move saidventuri downwardly, so as to cut oil the supply of air to the annularspace bet-ween the said venturi and the second venturi M, and the secondventuri M is so constructed and arranged that a continued movement ofthe actuating device employed to shift the venturi L will cause saidsecond venturi M to be moved into such a position as to cut oil thesupply of air to'the annular air passageway of same and also to theannular air passageway of the third venturi In the form of my inventionherein shown the first venturi L is reciprocatingly mounted in the bodyof the carburetor and the second venturi Nis sustained or carried by ayielding supporting structure composed of two reversely arranged,cup-shaped members 5 and 6, as shown in the drawings, the member 5 beingarranged with its side wall project ing upwardly and disposed oppositelyto a flange 7 on the lower end of the venturi L, and the member 6 beingarranged with its side wall projecting downwardl thereby permitting airto pass from the air chamber D through the s ace between the top edge ofthe on 5 and the flange 7 and through the space Between the edge of theinverted cup 6 and the bottom wall of the air chamber l) when the partsare in the positions shown in Figures 2 and 3. The yielding supportingstructure that carries the second venturi M is sustained and normallymaintained in the position shown in Figures 2 and 3 by springs Means isprovided for enabling the operator in charge oil the engine to more theventuri l1 downwardly into. engagement with the cup 5, or downwardlystill farther so as to compress the springs 8, and thus cause the bottomedge of the cup 6 to engagethe bottom wall of the air chamber ll), saidmeans being herein illustrated as consisting of a manually-operablelever 9 attached to a stud 10 on an oscillating device 11 in the body ofthe carburetor that is prpvided at its inner end with aneccentrically-disposed pin 12 that enters a hole or annular groove 13 inthe exterior ofthe venturi L. When the lever 9 is rocked in onedirection, the venturi :llj will be moved downwardly, so as to cause theflange 7 thereon to engage the cup 6, thereby cutting off the supply ofair to the venturi L and facilitating the starting of the engine. Inextremely cold weather or zero weather a continued movement of theoperating mechanism that is used 'tto actuatethe lever 9, causes theventuri L to continue to move downwardly, after it has engaged the cup5, thereby compressing the springs 8, and causing the cup 6 tomovedownwardly into such a position that air cannot flow through the annularpassageway of the second venturi M, or flow downwardly into theaccelerating well H. As soon as the operator releases the operatingmechanism that is used to actuate the lever 9, the device 11 rocks inthe opposite direction under the in.-

fluence of a torsion spring let, thereby causing the venturi L to bemoved upwardly bacl: to its normal position, and permitting the springs8 to expand and restore the second venturi M to its former normalposition shown in the drawings. lit will thus be seen that my improvedcarburetor is provided with two separate and distinct choking devices,one consisting of the first venturi L that is capable of being shiftedinto such a position as to cut ofl the supply of air to a same inmoderate weather, and the other out of consisting of the yieldingsupporting structure that carries the second 'venturi M and which iscapable of being shifted into such a position in zero weather orextremely cold weather as to cut oil' the supply of air to the secondand third venturis. At such times, i. e., after the venturi L has beenmoved downwardly far enough to cause the bottom edge of the inverted cup6 to be pressed against the bottom of the air chamber D, and thus cutoff the supply of air to the annular passageways of all of the venturis,air will be supplied to the fuel passageway of the nozzle l by an airduct 15 whose intake end s in communication with the atmosphere andwhose discharge end is in communication with an air orifice 16 locatedbeneath the fuel nozzlell at'the center of an annular fuel passageway 17from which. the nozzle I receives its supply of fuel, the air that flowsupwardly through the orifice 16 becoming mixed with the fuel that isdrawn upwardly the fuel passageway 17 by the suction exerted on-thenozzle, and thus producing an aerated charge that greatly facilitatesthe starting of the engine. The air duct 16 not only supplies air to thecenter passageway of the nozzle 1 when the carburetor is choked, but italso supplies air to said nozzle at all other times, when the suctionexerted on the upper end of the nozzle is suflicient to cause fuel to bedrawn upwardly into said nozzle from the annular fuel passageway 17, atthe lower end of the nozzle. Accordingly, in my improved carburetormeans is provided for introducing an aerated jet of fuel directly intothe third venturi'O of the carburetor located at the upper end of thenozzle l. The duct 15 that supplies air to the orifice 16 beneath thenozzle can be formed in various ways without departing from the spiritof my invention. In the carburetor herein shown the inlet end of the airduct 15 terminates in "a ball-shaped portion 18 on a standard 19 thatserves as a support for the piston 20 of a ump of the kind shown in myapplica ion erial No. 359,096 filed of even date herein, but ll wish itto be understood that said pump forms no part of my present invention.The ball-shaped portion 18 just referred to is arranged in a socket 21on the underside of the pump piston 20, and the retaining plate 22 inthe lower end of the piston that holds said ball in its socket isprovided with air inlets 23 that establish communication between theatmosphere and the socket 21 in the piston, and thus permits air toenter the passageway 15 and flow to the air orifice 16 beneath the fuelnozzle.

Fuel is supplied from the float chamber E to the lower end of theaccelerating well H by a fuel orifice or duct 24, as shown in Figure 2.A separate fuel supply duct or orifice 25, also shown in Figure 2, isprovided for admitting fuel from the float chamber to the annular fuelpassageway 17 located at the lower end of the fuel nozzle. The fuel duct25 is preferably made large enough so that it is not liable to becomeclogged with foreign matter in the fuel, and in order to prevent saidduct 25 from supplying too much fuel to the nozzle at high speeds, thecarburetor is equipped with a fuel economizing device that consists ofan air vent 26 that leads from the upper end of the float chamber E tothe upper portion of the accelerating well H. When air is flowing fromthe air chamber 1) downwardly through the well H, said flowing stream ofair creates .a suction or partial vacuum in the upper portion of thefloat chamber that is exerted on the fuel in the float chamber in such amanner as to retard the escape of fuel from the float chamber throughthe duct 25 that leadsto the fuel passageway 17, thereby effecting aconsiderable saving in the consumption of fuel at high speeds. The airthat is supplied to the orifice 16 through the air duct 15 also has atendency to reduce the quantity of fuel which the nozzle it introducesinto the main passageway imcertain positions of the throttle valve, dueto the fact that the air which flows upwardly from the orifice 16 intothe fuel passageway of the nozzle it cuts down the suction that iscreated insidecof the nozzle. It is f tle valve is moved into its wideopen position,

said means being of such a character that it increases the proportion ofthe fuel relatively'to air, that is supplied to the nozzle when thethrottle valveis wide open. In addition to modifying the action oreffect produced by the fuel economizing device, said means alsocompensates for the diminution of the discharge of the fuel froni'thenozzle, produced by the admission of air to the interior of the nozzlethrough the'air duct 15 and air orifice 16. In the form of my inventionherein illustrated the means above referred to consists of an air vent Pleading from the upper portion of the float chamber to the air chamber Dof the carburetor, and a valve or closure R for said vent P that isgoverned by the throttle valve shaft 27. The

valve R consists of a vertically-disposed rod mounted in the body of thecarburetor and provided at its lower end with a projection 28 that isadapted to enter a reduced portion of the air vent P and serve as aclosure for same. When the throttle valve A is in its closed orintermediate positions the valve rod R is engaged by the throttle valveshaft and maintained in such a position that the projection 28 thereoncuts off communication between the air chamber D and the upper portionof the float chamber, but when the throttle valve is moved into its wideopen position, a flat rtion 27 on the throttle valve shaft comes intoregistration with the upper end of the valve rod-R, thereby permittingsaid rod to move .upwardly under the influence of a spring 29, with theresult that the projection 28 on the valve rod will bewithdrawn from theair vent P, thereby establishing direct communication between the upperportion of the float chamber and the air chamber D of the carburetor.Due to the fact that the air chamber D is under a lower pressure thanthe accelerating well to which the air vent 26 leads, the effectproduced by opening the air vent P is to reduce the suction or partialvacuum that exists in the upper end of the float chamber, therebymodifying or reducing the retarding efl'ect produced by the air vent 26and permitting the fuel to flow freely from the float chamber throughthe duct 25 to the nozzle I, and consequently, increas' ing theproportion of fuel relatively to air, to

such an extent that the nozzle will supply suificient fuel to the mainpassageway A to effectively take care of the condition that exists whenthe engine is subjected to a heavy load with awide open throttle,as, forexample, when the automobile propelled by the engine is pulling throughsand or pulling up a steep grade. It is, of course, immaterial whatparticular type or kind of valve or the like is used to open and closethe air vent P leading from the upper portion of the float chamber, andwhile I have stated that said air vent P preferably leads to the airchamber D of the carburetor, this is not essential. The essential thing,so far as this feature of my invention is concerned, is that the airvent P lead to theatmosphere or to an air passageway or chamber that isunder a materially lower pressure than the pressure which exists in theupper end of the accelerating well when air is flowing downwardlythrough the same. As previously stated, the auxiliary air vent P and thethrottle-controlled governing device for same not only modifies theaction of the fuel economizing device consisting of the air vent26, butit also compensates for the diminution in the discharge of fuel from thenozzle I into the'third venturi 0, produced by admitting air to theinterior of the nozzle through the orifice 16 and air duct 15.

By constructing the carburetor in the manner described I not only obtaina free vacuum carburetor that is exceptionally-economical in theconsumption of fuel, but I also obtain a carburetor in which the volumeof fuel relatively to air for the fuel nozzle I, will be increasedsufficiently when the throttle valve is moved into its wide openposition to insure the main passageway A being supplied with arelatively great quantity of fuel at times when the engine is operatingunder a heavy load with a wide open throttle.

Having thus described my invention, what I claim and desire to secure byLetters Patent 1. A carburetor provided with'a main passageway, athrottle valve for saidmain -passageway, a main fuel supply device, aplurality of venturis arranged in superimposed and concentric relationbetween the throttle valve and said fuel supply device, means forenabling the venturi that produces the first stage of suctionamplification to be moved tion a position wherein it serves as a chokingdevice which cuts off the supply of air to said first venturi, and meanswhereby the venturi ill) dll

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inseam? ity of venturis arranged in superimposed and concentric relationbetween the throttle valve and said fuel supply device, a shiftablestructure that carries the second venturi, an operating device that isadapted to be actuated to move the first venturi into engagement withsaid shiftable supporting structure to cut ed the supply of air to thefirst venturi, and means whereby continued movement of said actuatingdevice-causes said supporting structure to be moved into such a positionthat the supply of air is cut ed from the annular passageways of thesecond and third venturis.

3. A carburetor provided with a main passageway, a throttle valve forsaid main passageway, a main fuel supply device, a plurality of venturisarranged in superimposed and concentric relation between the throttlevalve and said fuel supply device, a shit'table supporting structurethat carries the second venturi, springs for sustaining said supportingstructure, and a means that is adapted to be actuated to shift the firstventuri into a position to cut oil the supply of air to the annularpassageway of same and to thereafter move said spring sustainedsupporting structure into such a position as to cut oil the supply ofair to the annular passageways of the second and third venturis.

i. A carburetor provided with a main passageway, a throttle valve forsaid passageway, a main luel supplying device, anlair orificecommunicating with the atmosphere, through which air passes into theinterior ofsaid fuel supplying device, a plurality of venturis arrangedin superimposed and concentric relation between said fuel supplyingdevice and said throttle valve, a supporting structure for the secondventuri consisting of two reversely arranged, cup-shaped members, one ofwhich is dis osed oppositely to the lower end of the first venturi andthe other being disposed oppositely to the bottom of the air chamber ofthe carburetor, springs for sustaining said supporting struc ture, andmeans whereby the first venturi can be moved downwardly into engagementwith the cup-shaped member disposed oppositely to same and thereafterdownwardly still farther so as to cause the reversely arranged,cup-shaped member to bear against the bottom wall of the air chamber,for the purpose described.

5. A carburetor provided with a main passageway, a throttle valve forsaid main passageway, a main fuel supplying device, a plurality ofventuris arranged in superimposed and concentric relation between saidthrottle valve and fuel supplying device, an air chamher, anaccelerating well communicatin at its upper end with said air chamber anarranged so that the air supplied to the annu= lar passageway of thethird'venturi ncust flow downwardly through said well, means forenabling the position of the first and second venturis to be changed soas to cut otl the how of air from said air chamber to said first andsecond venturis and to the accelerating well, and an air duct throughwhich air is admitted to said fuel supplying device,

a A carburetor provided with a main passageway, a throttle valve forsaid passageway, a main fuel supplying device, three venturis arrangedin superimposed and in concentric relationship between said throttlevalve and said fuel supplying device, a float chamber, a fuel outlet ofrelatively great cross-sectional area leading from said float chamber tosaid fuel supplying device, an air duct through which air is supplied tothe interior oil said fuel supplying device, and means governed by thethrottle valve for varying the pressure that exists in the float chamberabove the level of the fuel therein,

for automatically increasing the proportion of fuel that is admitted tothe fuel supply ingdevice when the throttle valve is movedinto its wideopen position,

7. A carburetor provided with a main pas sageway, a throttle valve forsaid passageway, an air chamber, a fuel nozzle, an accelcrating wellsurrounding said nozzle and arranged with its upper end communicatingwith said air chamber, three venturis arranged in superimposed andconcentric relationship between the nozzle and the throttle valve, afloat chamber, means for permitting liquid "fuel to pass from the lloatchamber to said nozzle and to said accelerating well,

an air orifice arranged so as to discharge a jet of air upwardly intosaid nozzle, means whereby the position of the first and second venturismay be changed to cut oil the suply of air to the annular passageways ofall of the venturis, and a means governed by the throttle valve forvarying the pressure that exists in the upper portion of the floatchamber above the fuel therein, according to the position of thethrottle valve,

8. A carburetor provided with a main passageway, a throttle valve forsaid main passageway, a main fuel sup ly device, a plurality of venturisarranged in superimposed relation between the throttle valve and saidfuel supplying device, means for enabling one or said venturis to bemoved into a position wherein it serves as a cholring' device that cuts0d the sup 1y of air to said venturi, and means where y a venturi thatproduces a difierent stage of suctionamplification can be moved into aposition to cut od the supply of air to all oil the venturis.

WILLIAM C. CARTER.

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